One way to reduce the intensity of a light beam is to pass the light beam through a light absorbing medium. The intensity of the exiting light beam can be controlled by selecting a light absorbing medium with the desired attenuation. Light absorbing mediums having fixed attenuation are well known in the optics field.
While using a light absorbing medium with a fixed attenuation is an effective way to control the intensity of a light beam in a static and/or predictable environment, optical systems such as lasers, light emitting diodes (LEDs), liquid crystal displays (LCDs), and charged coupled devices (CCDs) often have dynamic and/or unpredictable optical characteristics. The dynamic and/or unpredictable nature of many optical systems can make it difficult to effectively control the optical systems using light absorbing mediums with fixed attenuation properties. For example, as the output characteristic of an LED or LCD panel degrades, an installed light absorbing medium with a fixed attenuation may no longer provide the ideal attenuation for the system. Additionally, because LEDs from the same batch do not always have the same optical output, light absorbing mediums with different attenuation properties may need to be matched with LEDs on a per-LED basis to produce a batch of LED based products with the same optical characteristics.
In view of this, what is needed an optical element with an attenuation that can efficiently be adjusted to meet the needs of a specific application.